A video tape recorder (VTR) or a tape recorder is a device which records and reproduces audio and/or video signals on a magnetic tape. When one uses such a device for the purpose of linguistic drill or athletic exercise, there is often a need to repeatedly reproduce a certain portion of the recorded tape.
A typical conventional method for this purpose is performed using "endless tape (or drum, sheet)". The endless tape is a fixed-length magnetic tape which is endlessly circulated in the deck. Thus, one can record data in any section of the tape and reproduce that data repeatedly. This method cannot be used to reproduce video signals in video equipment owing to its complicated construction. Moreover, when the amount of recorded data is not equal to the endless tape's recording capacity, the wait time after reproduction increases. Thus, the less data recorded on the endless tape, the longer the wait time becomes. To solve this problem, many solutions, for example, detecting the non-recorded section and jumping to the start of the recorded section of the tape have been proposed. However, these methods are difficult to adapt to the reproduction of video signal.
Another conventional repeat reproduction method was disclosed in Japanese patent laid-open Publication No. Sho 6352356, which describes two decks in line and two magnetic tapes, each of which contains the same data. The two magnetic tapes are loaded in each deck, respectively, and the decks repeatedly reproduce the data in such a way that one tape is rewinding while the other tape is playing, and vice versa.
This method can be adapted to the repeat reproduction of not only audio signals but also video signals, but the method still has some drawbacks. In particular, it is very difficult to synchronize the advancing speeds of two tapes which are moving in opposite directions. The system cost is very high as it has two decks to pick up two tapes, respectively.